Smart Choice of Building Materials to Cool Cities

In recent years, Australia has continued to come up with solid strategies to help make cooler cities across the country. Through research, partnership and collaboration with researchers, the local government hopes to fight climate change and the urban heat island effect.

It is crucial for future urban developments to collaborate in order to combat the ever rising urban temperatures in major Australian cities. Things like designing cooler outdoor spaces with plenty of trees and vegetation and creating high-rise buildings that block the heat of the sun are some of the few things to consider when managing high temperatures, especially during summer.

In August 2017, through a collaborative effort, the Australian industry, local government leaders, and researchers came together at a national forum to review and evaluate the progress. Australia’s first guide to urban cooling was also launched and discussed among the industry leaders.

Authored by research leader, UNSW’s Dr. Paul Osmon, the guide is designed to keep urban residents cooler during hot weather by helping landscape architects, planners, urban designers, local authorities, and urban developers mitigate the urban heat island effect. Osmond said the document is a compilation of data based on a three-year project studying urban microclimates, covers different climate zones, and provides a toolkit for building planners.

“The range of urban landscapes that the guide covers include dense inner cities, middle ring and outer suburbs with a focus on design intervention, including streetscapes, plazas, squares and malls,” he said.

“The importance of design which embraces vegetation cover, particularly tree canopy; the use of shade to minimise heat; and the orientation of these elements are also key to cooling. Interventions may be active, such as misting systems and awnings, or passive, like street trees, green roofs, water bodies, cool roofs and facades.”

“All these elements have an effect on urban temperatures. For example, radiant temperatures in urban parks with sufficient irrigation can be two to four degrees Celsius cooler compared with adjacent unvegetated or built-up areas, while air temperature reduction may be up to two degrees Celsius according to a park’s extent and the proportion of trees. This is is known as the park cool island effect.” He added.

Urban climates are created from a balance between the heat of the sun and heat lost from walls, roofs, and ground. It is also brought about by heat exchange through air movement between ground, buildings, and atmosphere, as well as heat generation within the city itself through mobile transportation. The guide provides a framework of urban form, climate type and nature of heat intervention.

Building materials are also key aspects in contributing to UHI; therefore it is important to use materials that reflect the heat off buildings to reduce indoor temperatures. Collaborating with BlueScope Steel is highly recommended as they are a leader in sustainable, reflective building materials.